Yes. You have three limiting factors in a PC.
Most PCs on the market have small cases that only allow for 2-3 drives.
The next limit is your powersupply as you need to have a powersupply that can handle the load and has the appropriate connections.
The last limiting factor is your motherboard. The motherboard only has so many connections for drives. some motherboards only support 2 drives, including the DVD-RW drive while some motherboards have 10 or more connections.
Our server and our bench PC both have 3 drives. If you come into the shop, take a look at our clear bench computer. There you can see all the drives and the connections for them as well as ask any questions.